Log alembic migration script's output with oslo_log

Instead of using alembic.utils messages function which
prints output to stdout, lets use oslo_log logger to log
all such commands.
For logging error message alembic.utils module is still used
as those messages are quite important and should be displayed
to user in case of error.

This is needed to limit amount of output on stdout during
functional tests running on python3.5.

Change-Id: I20327bd1d5f784e021e9e1f1cbba1ef654271bfb

neutron/db/migration/cli.py

@@ -23,6 +23,7 @@ from alembic import migration as alembic_migration
 from alembic import script as alembic_script
 from alembic import util as alembic_util
 from oslo_config import cfg
+from oslo_log import log as logging
 from oslo_utils import fileutils
 from oslo_utils import importutils
 import six
@@ -32,6 +33,7 @@ from neutron.conf.db import migration_cli
 from neutron.db import migration
 from neutron.db.migration.connection import DBConnection
 
+LOG = logging.getLogger(__name__)
 
 HEAD_FILENAME = 'HEAD'
 HEADS_FILENAME = 'HEADS'
@@ -67,16 +69,16 @@ def do_alembic_command(config, cmd, revision=None, desc=None, **kwargs):
 
     project = config.get_main_option('neutron_project')
     if desc:
-        alembic_util.msg(_('Running %(cmd)s (%(desc)s) for %(project)s ...') %
-                         {'cmd': cmd, 'desc': desc, 'project': project})
+        LOG.info('Running %(cmd)s (%(desc)s) for %(project)s ...',
+                 {'cmd': cmd, 'desc': desc, 'project': project})
     else:
-        alembic_util.msg(_('Running %(cmd)s for %(project)s ...') %
-                         {'cmd': cmd, 'project': project})
+        LOG.info('Running %(cmd)s for %(project)s ...',
+                 {'cmd': cmd, 'project': project})
     try:
         getattr(alembic_command, cmd)(config, *args, **kwargs)
     except alembic_util.CommandError as e:
         alembic_util.err(six.text_type(e))
-    alembic_util.msg(_('OK'))
+    LOG.info('OK')
 
 
 def _get_alembic_entrypoint(project):
@@ -248,10 +250,10 @@ def _compare_labels(revision, expected_labels):
         bad_labels_with_release = (revision.branch_labels -
                                    _get_release_labels(expected_labels))
         if not bad_labels_with_release:
-            alembic_util.warn(
-                _('Release aware branch labels (%s) are deprecated. '
-                  'Please switch to expand@ and contract@ '
-                  'labels.') % bad_labels)
+            LOG.warning(
+                'Release aware branch labels (%s) are deprecated. '
+                'Please switch to expand@ and contract@ '
+                'labels.', bad_labels)
             return
 
         script_name = os.path.basename(revision.path)
@@ -346,8 +348,8 @@ def validate_head_files(config):
     contract_head = _get_contract_head_file_path(config)
     expand_head = _get_expand_head_file_path(config)
     if not os.path.exists(contract_head) or not os.path.exists(expand_head):
-        alembic_util.warn(_("Repository does not contain HEAD files for "
-                            "contract and expand branches."))
+        LOG.warning("Repository does not contain HEAD files for "
+                    "contract and expand branches.")
         return
     head_map = _get_heads_map(config)
     _check_head(CONTRACT_BRANCH, contract_head, head_map[CONTRACT_BRANCH])
@@ -387,11 +389,11 @@ def has_offline_migrations(config, cmd):
         # it means we should shut down all neutron-server instances before
         # proceeding with upgrade.
         project = config.get_main_option('neutron_project')
-        alembic_util.msg(_('Need to apply migrations from %(project)s '
-                           'contract branch. This will require all Neutron '
-                           'server instances to be shutdown before '
-                           'proceeding with the upgrade.') %
-            {"project": project})
+        LOG.info('Need to apply migrations from %(project)s '
+                 'contract branch. This will require all Neutron '
+                 'server instances to be shutdown before '
+                 'proceeding with the upgrade.',
+                 {"project": project})
         return True
     return False
 
@@ -651,6 +653,6 @@ def main():
         return_val |= bool(CONF.command.func(config, CONF.command.name))
 
     if CONF.command.name == 'has_offline_migrations' and not return_val:
-        alembic_util.msg(_('No offline migrations pending.'))
+        LOG.info('No offline migrations pending.')
 
     return return_val

neutron/tests/unit/db/test_migration.py

@@ -123,7 +123,7 @@ class TestCli(base.BaseTestCase):
         self.do_alembic_cmd_p = mock.patch.object(cli, 'do_alembic_command')
         self.do_alembic_cmd = self.do_alembic_cmd_p.start()
         self.mock_alembic_err = mock.patch('alembic.util.err').start()
-        self.mock_alembic_warn = mock.patch('alembic.util.warn').start()
+        self.mock_log_warn = mock.patch.object(cli.LOG, "warning").start()
         self.mock_alembic_err.side_effect = SystemExit
 
         def mocked_root_dir(cfg):
@@ -419,7 +419,7 @@ class TestCli(base.BaseTestCase):
                 cli.validate_head_files(fake_config)
             elif head_files_not_exist:
                 cli.validate_head_files(fake_config)
-                self.assertTrue(self.mock_alembic_warn.called)
+                self.assertTrue(self.mock_log_warn.called)
             else:
                 self.assertRaises(
                     SystemExit,